Gas turbine engines are the preferred class of internal combustion engine for many high power applications. Fundamentally, a gas turbine engine features an upstream rotating compressor coupled to a downstream turbine, and a combustion chamber in-between. The combustion chamber can include multiple fuel/air mixer assemblies to mix fuel and air for combustion. Fuel can be supplied to the combustion chamber in a staged combustion scheme, where the fuel injectors or fuel/air mixers are divided into groups or stages, typically two to four stages. Each stage can be operated separately to provide optimal emission and operability of the engine across full power range by turning on the combustion sequentially in stages.
When the engine operates at lower power settings, only one or some of the stages are turned on to flow fuel for combustion. The remaining stages are off and have no fuel flow but airflow, in order to maintain adequate flame quality such as combustion stability and efficiency.
When the engine operates at higher power setting, where the combustor's environments are harsher, all stages of fuel injector or fuel/air mixers are turned on so to spread out the fuel flow across the combustor dome evenly so to minimize the damaging hot flame streaks and the resulting high emissions that may otherwise exacerbated by uneven distribution of fuel and flames if some stages were left off.
Like reference symbols in the various drawings indicate like elements.